As electronic devices are increasingly used, technology for increasing a battery capacity or optimizing battery power consumption is developing, and technology for optimizing power consumption in wireless communication systems to reduce battery power consumption is developing. Envelope tracking (ET) technology and average power tracking (APT) technology are used to optimize power consumption of a power amplifier constituting part of a wireless communication system. The ET technology and the APT technology achieve high efficiency by reducing power loss by changing a supply voltage to the power amplifier according to output power of the power amplifier.
The ET technology may not provide a capacitor which is typically arranged at a bias voltage input terminal of a power amplifier to apply an alternating current voltage and to remove a noise. Accordingly, since the capacitor typically arranged at the bias voltage input terminal is not provided for the sake of minimizing power consumption in a wireless communication system, there may be a problem that the power amplifier is vulnerable to noise.